The present invention relates to a process cartridge and a mounting mechanism (mounting-and-demounting mechanism) for a process cartridge, and an electrophotographic image forming apparatus.
Here, the electrophotographic image forming apparatus forms an image on a recording material through an electrophotographic image-formation-type process. Examples of the electrophotographic image forming apparatus include an electrophotographic copying machine, an electrophotographic printer (a laser beam printer, an LED printer or a like), a facsimile machine, a word processor or a complex machine (multi-function printer or the like) or the like.
The process cartridge integrally contains an electrophotographic photosensitive drum, and charging means, developing means or a cartridge, in the form of a unit or a cartridge, which is detachably mountable to a main assembly of an image forming apparatus. The process cartridge may contain the electrophotographic photosensitive drum, and at least one of charging means, developing means and cleaning means, in the form of a cartridge which is detachably mountable to the main assembly of the image forming apparatus. Or, it may be a cartridge containing integrally at least developing means and an electrophotographic photosensitive member, the cartridge being detachably mountable to a main assembly of an image forming apparatus.
In an electrophotographic image forming apparatus using the electrophotographic image forming process, use has been made of process-cartridge type in which the process cartridge comprises as a unit the electrophotographic photosensitive member and process means actable on the electrophotographic photosensitive member, the unit being detachably mountable to the main assembly of the electrophotographic image forming apparatus. With the use of the process-cartridge-type apparatus, the maintenance operation can be carried out in effect by the users without the necessity of relying on a serviceman, and therefore, the operability is improved. Therefore, process-cartridge-type machines are widely used in the field of the image forming apparatus.
In order to provide satisfactory images by the electrophotographic image forming apparatus using such a process cartridge, it is necessary that the process cartridge is mounted at a predetermined position in the main assembly of the electrophotographic image forming apparatus to establish a correct connection of the interface portions such as various electrical contacts and a drive transmitting portion.
Referring first to FIG. 60 and FIG. 61, there are shown a process cartridge PC (FIG. 60) and a guide groove GL provided in the main assembly PR of the image forming apparatus (FIG. 61). FIG. 62 shows an image forming apparatus employing such a process cartridge PC.
As shown in FIGS. 60-62, in the mounting-and-demounting of the process cartridge PC relative to the main assembly PR of the image forming apparatus, a positioning boss CB is provided on the axis of an electrophotographic photosensitive member in the form of a photosensitive drum provided in the process cartridge PC, and on the other hand, the main assembly PR of the image forming apparatus is provided with a guide groove GL for guiding and positioning the positioning boss CB of the process cartridge. When the user inserts the process cartridge PC along the mounting guide (cartridge mounting guide) to a predetermined position, an abutting portion P provided on the main assembly PR of the image forming apparatus is abutted to the process cartridge PC to prevent rotation about the positioning boss CB. The apparatus of such a structure has been put into practice.
As shown in FIG. 62, the process cartridge PC is provided with a drum shutter DS which functions to cover the surface of the photosensitive drum when the process cartridge PC is out of the main assembly PR of the image forming apparatus and to expose the surface of the photosensitive drum when the process cartridge PC is mounted in the main assembly PR of the image forming apparatus. The opening and closing of the drum shutter DS is carried out in interrelation with an inserting operation of the process cartridge PC into the main assembly PR of the image forming apparatus or with the removal thereof.
An urging means for urging the process cartridge PC in the mounting direction has been proposed and put into practice, wherein the charging means is provided on the opening and closing cover C of the main assembly PR of the image forming apparatus.
As shown in FIG. 62, another proposal has been made in which a back cover UC having a shape corresponding to the outer configuration of the process cartridge PC is fixed to the inside of the cover C, and the process cartridge PC is urged to a regular position by closing the cover C.
The present invention provides a further development of the prior-art technique.
Accordingly, it is a principal object of the present invention to provide a process cartridge and an electrophotographic image forming apparatus to which the process cartridge is detachably mountable, in which the mounting operability for mounting the process cartridge to the main assembly of the apparatus, is improved.
It is another object of the present invention to provide a process cartridge and an electrophotographic image forming apparatus to which the process cartridge is detachably mountable, in which the process cartridge can be automatically mounted to the mounting position of the main assembly of the apparatus.
It is a further object of the present invention to provide a process cartridge and an electrophotographic image forming apparatus to which the process cartridge is detachably mountable, in which the process cartridge can be mounted to the mounting position of the main assembly of the apparatus in interrelation with a closing operation of an openable member.
It is a further object of the present invention to provide a process cartridge and an electrophotographic image forming apparatus to which the process cartridge is detachably mountable in which the process cartridge can be automatically mounted to or demounted from the mounting position of the main assembly of the apparatus.
It is a further object of the present invention to provide a process cartridge and an electrophotographic image forming apparatus to which the process cartridge is detachably mountable, in which the mounting-and-demounting operability of the process cartridge relative to the main assembly of the apparatus is improved.
According to an aspect of the present invention, there is provided a process cartridge and an electrophotographic image forming apparatus to which the process cartridge is detachably mountable to a main assembly of an electrophotographic image forming apparatus which includes an openable closing member, a first main assembly side guide movable in interrelation with the opening and closing action of the closing member, and a second main assembly side guide, the process cartridge comprising: an electrophotographic photosensitive drum; process means actable on the photosensitive drum; a first cartridge frame portion extending in a direction in which the cartridge is mounted to the main assembly of the apparatus, at one axial end portion of the photosensitive drum; a first cartridge guide projected from the first cartridge frame portion, the first cartridge guide moving the cartridge toward a cartridge mounting position by movement of the first main assembly side guide with the cartridge being supported on the first main assembly side guide, when the cartridge is mounted to the main assembly of the apparatus; a second cartridge frame portion extending in the mounting direction at the other axial end portion of the photosensitive drum; a second cartridge guide projected from the second cartridge frame portion, the second cartridge guide moving the cartridge toward a cartridge mounting position by movement of the second main assembly side guide with the cartridge being supported on the second main assembly side guide, when the cartridge is mounted to the main assembly of the apparatus; a first cartridge positioning portion for engaging with a first main assembly positioning portion provided in the main assembly of the apparatus to position the process cartridge relative to the main assembly of the apparatus when the process cartridge is mounted to the main assembly of the apparatus, the first cartridge positioning portion being projected outwardly from the first cartridge frame portion and coaxially with the photosensitive drum at the one axial end of the photosensitive drum; and a second cartridge positioning portion for engaging with a second main assembly positioning portion provided in the main assembly of the apparatus to position the process cartridge relative to the main assembly of the apparatus when the process cartridge is mounted to the main assembly of apparatus, the second cartridge positioning portion being projected outwardly from the second cartridge frame portion and coaxially with the photosensitive drum at the other axial end of the photosensitive drum.
These and other objects, features and advantages of the present invention will become more apparent upon a consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings.